Time switch with omitting mechanism



Jan. 26, 1960 F. w. TRUESDELL 2,922,353

TIME swncn WITH OMITTING MECHANISM 3 Sheets-Sheet 1 Filed June 20, 1958 Fig.l

INVENTORS George 0. Baker Their Afforney Jan. 26, 1960 F. w. TRUESDELL ET 2,922,853

TIME SWITCH WITH OMITTING MECHANISM Filed June 20, 1958 3 Sheets-Sheet 2 INVENTORS George 0. Baker BY Francis W.Truesde H heir AHorn ev Jan. 26, 1960 F. w. TRUESDELL ET'AL 2,922,853

TIME SWITCH WITH OMITTING MECHANISM Filed June 20, 1958 3 Sheets-Sheet 3 43 Fig.3

IINVENTORS George 0. Baker Their Arforney United States Patent TIME SWITCH WITH OMITTING MECHANISM Francis W. Truesdell, Dover, and George 0. Baker,

Rochester, N.H., assignors to' General Electric Company, a corporation of New York Application June 20, 1958, Serial No. 743,363 6 Claims. ((31. 200-'-38) This invention relates generally to improvements in time switches and, more particularly, to a novel arrangement of parts which permits a standard time switch to have an omitting mechanism added thereto; I

It has been a common practice to provide time switches with omiting mechanisms whereby for preselected days the time swtich is prevented from performing its usual switching operations, and in the past the provision of omitting mechanisms usually involved extensive modifications to standard time switches which materially added to the cost and complexity of the switch. Moreover,

the added complexity in many instances led to increased maintenance problems, which in most-installations of time switches is highlyundesirable 1 Accordingly, it is a primary object of this invention to provide an omitting mechanism for a standard time switchwherein the omitting'action is accomplished with a minimum number of added parts at a minimum increase inmanufacturing cost.

It is another object of the invention to provide an omitting mechanism for a time switch which is extremely simpleto install and which functions reliably without requiring anything more thannormal maintenance and service.

The invention as well as its objects'and advantages will be readily'understood upon reference to the-following detailed description, particularlywhen taken in conjunction with the three sheets of drawings annexed hereto in whichz V Figure 1 is a partially cut away front view, in elevation, of a time switch embodying the novel omitting mechanism;

Figure 2 is an exploded partial view of the time switch shown in Figure 1, without the omitting mechanism;

Figure 3 is a partial view of the time switch shown in Figure 1, with a number of the parts cut away showing thefnormal at-rest position of the omitting mechanism;

Figure 4 is a view similar to Figure 3 showing the position o-f'the time switch just prior to the completion of anomitting action; 7

Figure 5 is a sectional view taken along the lines 55 in-Figure 4; and

Figure 6 is a sectional view taken along the lines 6-6 in Figure 1. I

Referring now to the drawings, the time switch and its novel omitting mechanism are mounted on a main support plate7, which, inturnfmay be suitably mounted in any'convenient housing" to makeu a finished switch. The time switch, without the addition of thenovel omitting mechanism, may be ofth'e kind'sold commercially by the assignee of this application under the designation of Type TGW7 Time'Switch, and its underlying principle of operation'is disclosed in United States Patent N .2,020,974, issued to Francis 'W.'Truesdell, and now be one 'of; the well known Telechron synchronous motors,

WhiCh'dn'v'es a earn 9 through'a con'ipleterevolu- 2,922,853 Patented Jan. 26, 1960 -15, which forms a part of the gear train 11 and is mounted concentrically with respect to the timing cam. The bushing surrounds a stud shaft (not shown) fastened to support plate 7, with the gear 15 suitably spaced from the plate and the gear and cam assembly held in place on thestud shaft-by the hub of a pointer 17, which in turn is rigidly affixed to the stud with a screw 18; For manually resetting the timing cam, an auxiliary gear is rotatably mounted on plate 7, engaging at all times the gear 15 and turning with it during normal operation of the time switch. The gear 14 includes a setting knob 16 rigidly attached thereto so that one can turn the gear 14 for manual resetting. A conventional spring clutch built into the gear train 11 permits such manual resetting.

The timing cam is in the form of a circular dial 19 having a twenty-four-hour scale 21 printed thereon, with a pair of Olftrippers 22'mounted at spaced points on the peripheral edge of dial 19 and a pair of spaced On trippers 23- also mounted along the peripheral edgetof dial 19.'Each of these trippers is held in place by means of a screw 24, and the dial is grooved at 25 to provide a seat for the screws so that the trippers will remain securely in-place on the dial once their position has been set. If it is desired to reposition any of the trippers, the screw 24 can be loosened slightly, and the trippers will then slide around the groove until the new setting point is reached, after which the screw is tightened in place and the switch is then ready for continued action.

Each of the trippers is provided with cam surfaces with the cam surface 22a of the-Otftrippers lying behind the dial 19, and the cam surface 234 of the On trippers lying in front of the dial.

Switch actuating arm 12 has its end 12a formed'as a U-shaped yoke, which slips over a stud shaft 26 aflixed to plate 7, with the inner leg of the yoke suitably spaced from the plate, and a snap ring 27 against the outer leg of the yoke and cooperating withthe stud shaft 26 to hold the switch actuating arm in place. The aforesaid arrangement provides a pivotal mounting for the switch actuating arm, and towards the outer end of the arm, there is aflixed an insulating post 28, which cooperates with the electrical switch 13 to 'give the necessary switching action as the arm 12 pivots, with the plate 7 cut out at 29 to' allow clearance for post 28; The switch 13 is shown in part and comprises the spring blades 31, 32 on which are mounted the electrical contacts 33, 34. The switch and its associated mounting structure are fully shown in United States Patent No. 2,834,857,-issued May '13, 1958, to G. 0. Baker et al., and reference will be had to the aforesaid patent for a more detailed description of the electrical switch and mounting arrangements therefor.

A second electrical switch 35, substantialy identical in all respects to the-switch 13, may also be included in the time switch and actuated by an extension 28a of post 28. This second switch may be arranged to open when switch 13 closes, and vice versa.

To actuate the arm 12 and open and close the contacts of the associated electrical switches with a snap action, the principle of operation shown in the aforesaid Truesdell Patent No.2,020,974 is employed. Thus, the'switch has an Off trigger'36 pivotallymounted 'on' arm '12, connected to one end of a spring 37, with the other end of A spring 37 anchored to a part of support plate 7 which {and which extends through a cut out 12b formed in the arm 12. 7 I 7 An On trigger 39 is pivotally mounted on plate 7, having one end 39a formed as a U-shaped yoke which slips over astud shaft 40 affixed to plate 7 and on which it is retained by means of screw 41. The inner leg of the .On trigger yoke is suitably spaced from the plate 7, and the trigger has its outer end 39a turned inwardly at right 'angles to its main body. A torsion spring (not shown) may be afiixed to the On trigger to bias it in a counterclockwise direction toward the timing cam 9.

. The action of the time switch is'as follows: 'With the timing earn 9 rotating in a counterclockwise direction, ,and assuming first that one of the Offtrippers arrives "at the'location of the triggers (see Figure 2), the Off itripper cam'portion 22a will engage the Off trigger portion 36a and. move the Off trigger in a clockwise manner about its pivot, during which the spring 37 is stretched to store energy therein. As the Oif trigger extension 36a slips over the rise on the OE tripper cam surface 22a, the spring will snap the trigger back against thexedge of cut out.12b to the position shown in Figure l,

but in doing so it will move the arm 12 away from the timing cam 9 in a substantially radial direction relative to the cam and with'a snap action. During this movement of arm12, its stepped end will move away from the extension'39bformed as a part of the On trigger 39 and allow extension 39b to latch behindthe middle step 12c and hold the arm 12 in its Oif position. During this part of the switch cycle, the contacts 33, 34 will be opened by the post 2%, audit 9. second switch 35 is included, its contacts will be closed. Continued rotation of the timing cam will bring oneof the On trippers 23 near the On trigger 39, and the cam surface 2311 will engage the portion 39a and move the On trigger in a clockwise direction away from the timing cam, which movement will disengage the latching extension 39b from the middle step 12c, thereby allowing the arm 12 'to rapidly move back to its initial position until such time asthe outer step 12d contacts. the latching extension 38b, The .arm 12 thus moves between first and second positions in a substantially radial direction relative to timing cam 9, and such action would continue indefinitely. f To allow the user of such a switch to omit switch action on any particular day, a novel omitting mechanism has been added to the time switch, such mechanism comprising a timing pin 42 afiixed to gear 15, a. sevenpointed star wheel 43, a day wheel 44 on which are mounted seven circumferentially arranged, spaced omit- :ting pins 45, a detent spring 46, and an omitting arm 47. Both the star wheel 43 and the day wheel 44 are rotatably mounted on suitable stud shafts affixed to plate 7, and the omitting arm 47 is pivotally mounted on a stud shaft 48 aflixed to plate 7, being held in place thereon by a snap ring 49. "i As is best shown in Figure 6, the day wheel comprises a pair of spaced circular plates 51, 52, between which is -a split bushing 53, which retains in place a spring having 'seven radially extending spring arms 54 which have their outer ends confined within grooves 55 formed circumferentially in pins 45. The springs 54 allow the omitting pins to move between first and second positions toward and away from the omitting arm 47. The radial springs 54 provide a detent action in eitherposition of the omitt ng pins whereby the pins will hold the position in which they are set. i

The omitting arm 47 has one end formed with a cam surface 47a and the other end formed with an extension 47b turned at right angles. to t e main body of the 7 omitting arm and extending outwardly therefrom a sufficient distance to overlie the edge of switch actuating arm 12. The omitting arm is guided and supported by means of a pair of identical spaced posts 56 (as is best shown in Figure with each post having a shoulder at its upper extremity on which the edge of the omitting arm rests, with snap rings 57 being aflixed to the posts, overlying the omitting arm and forming with the shoulder a groove in the postfor guiding and supporting the peripheral edge of the omitting arm. 7

The omitting arm' 47 is biased in a counterclockwise direction away from the switch actuating arm by means of the spring 58, which has one end hooked through an aperture 59 provided in omitting arm 47 and its other end hooked through aperture 61 provided in support plate 7. The edge of the omitting arm which is supported and guided by the grooved posts 56 is formed into a stop at its outer extremity 470 to limit the rotation of the omitting arm caused ,by biasing spring 58; 20

With the above parts in mind, the operation of the omitting mechanism is as follows: The timing pin 42 will rotate with the timing cam and once each revolution will engagev one of the points of the 'star wheel 43 which lie in its path. When this occurs, the star wheel will be moved in a clockwise direction one-seventh of a revolution, with the timing pin engaging the point throughout such motion and then automatically disengaging itself from the point for continued rotation in synchronism with the timing cam. The position of the omitting mechanism'prior to engagement of the star wheel is shown in Figure 3, and its position just prior to disengagement of the star wheel is shown in Figure 4. As seen in Figures 1 and 3, the star wheel lies underneath the day wheel, and in its normal at-rest position one of the omitting 'pins 45 lies between adjacent star points and in their 'path. As the star wheel begins to move, one of its points will engage the trapped omitting pin and drive the day 'wheel for one-seventh of a revolution, with the parts at the end of this motion returning to the relative position shown in Figure 3.

If an omitting action is desired, and assuming for a moment that the switch actuating arm is in its Oif position furthest from thetiming cam 9, one of the omitting pins will be pushed inwardly toward the plate 7 to occupy the position shown in dotted lines in Figure 6, such that the cam surface 47 of the omitting arm lies in the path of the depressed pin as it moves with the day wheel. The omitting pin will thus engage the cam surface of the omitting arm and move the omitting arm in a clockwise direction a suflicient distance to bring the locking extension 47b down on the edge of the switch actuating arm 12. This position of the parts is' shown in Figure 4,

. whichis just prior to completion of the omitting cycle, with further movement of the omitting pin being along the cam surface 47a but behind it'such that it provides a positive stop holding the omitting arm in the omitting position.

With the arm 12 so held, as the timing cam rotates to actuate an On trigger, the release of the latch 39b will haveno eifect on switch operation, since the omitting arm continuesto hold the arm 12 in the Off position. Should an 011 tripper move past the Off trigger, there will be no switch action, as the parts will clear easily "without changing the position shown in Figure 4.

1f thenext succeeding days switch operation is tobe a normal one, rotation of the day wheel will cause the omitting pin which has been holding the arm 47 in the omitting position to clear the cam surface 47a and allow the spring 58 to move the omitting arm back to its normal position, with the am coming to rest when the stop 470 contacts its associated post 57. During the return motion of .arm 47, it will pass underneath the next succeeding omitting pin.

Should omitting action occur in two successive days, the 47 wil not return s it was P i h the v 5.- fif'sbomitting pinvclears cam surfa'ce 47d but: will only move back until "it.' isjlengaged 'by theflnext succeeding omitting pin, after which the arm .will'lbe driven once again to its omitting position.

It takes about two hours to complete the emitting cycle, i.e., for the star wheel and the day wheel to complete their one-seventh revolution, and for this reason it.is desirable. to have the omitting cycle always occur when the switch 'is in the Off position. When in the Oif position, the switchactuating arm 12 will be furthest from timing cam 9 and will not be disturbed by the omitting arm 47 as it slowly moves into its omitting position against the edge of arm 12. If the switch wereinthe On position, with the switch actuating arm in. its position nearest the timing cam, the arm 12 would be slowly driven to its Off position by the omitting arm, thereby producing a very slow and highly undesirable switch action.

As is shown in Figure 1, the day wheel has a series of letters arranged on its surface, each letter serving as a label for its associated omitting pin and corresponding to a separate day of the week. Thus, if omitting action is desired for one or all of the days of the week, it is only necessary to depress the desired omitting pins and leave them in that position until normal operation for a particular day or days is desired, at which time the pins are simply pulled out and returned to their inactive position. As shown in Figure 6, in the inactive position the pin has its inner end above the omitting arm such that the pin will pass over the arm without engaging it when omitting action is not desired.

To properly position the day wheel 44 when at rest, the detent spring 46 is provided, having its outer end 46a bearing against an omitting pin, and its inner end 46b formed with a flange that is securely mounted on plate 7 by means of the screws 62. The omitting mechanism is arranged so that the detent spring during the at-rest cycle always bears against that pin which corresponds to the day in which the time switch is operating, with the outer end turned over to form the indicating flag 460 which at all times is visible to provide a ready check on switch operation. In Figure l, a portion of the flag is visible showing that the switch is in its normal Tuesday position.

The detent spring is also formed into an angle, such that the portion 46d lies adjacent the next succeeding omitting pin when the outer end bears against its corresponding pin. This arrangement of the pin accomplishes a two-fold result, for it not only keeps a portion of the spring in constant engagement with an omitting pin, during both the at-rest and omitting cycles, but it allows the next succeeding pin to move the flag 46c outwardly from the day wheel during the omitting cycle so that more of the flag is exposed to indicate that the omitting cycle is underway. In Figure 4, the flag is shown pushed outwardly from where it will return to its normal position upon completion of the omitting cycle.

From the above, it is seen that an extremely simple arrangement of parts has been devised to provide an omitting action in a standard time switch. A minimum number of parts have been added to the time switch, without requiring any changes in the time switch per se, save for the addition of the timing pin 42. Moreover, the omitting mechanism is readily adapted to other forms of the time switch shown. For example, the timing cam could take the form of a dial having its peripheral edge contoured to form cam lows and cam rises, in place of the On and Off trippers, in which event the On trigger could be omittedsuch a timing cam being shown in the aforesaid Truesdell Patent No. 2,020,974. Also, it is not necessary to employ the snap-action principle of the Truesdell patent, for the omitting mechanism would work just as well with a slowly moving switch actuating arm that cooperates with a switch that has its snap action built in.

Therefore, while a particular embodiment of the invention has been shown and described herein, it is in the naanzejasa '6 tureof description rather..than...lirnitation, and occur to those skilled in the art that various changes;mod ifications, and combinations \may be made within'th'e province of the appended claims, and without departing either in spirit or scope from this invention in its broader aspects.

What we claim-as new and desire Patent of the United States is:

1. A time switch comprising, in combination: a rotatably mounted timing cam;'a rotatably mounted day wheel; means including a timing motor for driving said timingcam through a complete revolution in one day and for driving said day wheel through one-seventh ofa revolution in one day; said means for driving said day wheel including a timing pin which rotates in synchronism with said timing cam and a seven-pointed rotatably mounted star wheel located in the path of said pin whereby each time the pin completes a revolution it engages one of said star wheel points and moves said star wheel through one-seventh of a revolution; said day wheel having seven equally spaced omitting pins arranged circumfcrentially thereon, said omitting pins being located in the path of said star wheel whereby each time said star wheel is moved one of its points engages a corresponding omitting pin to drive the day wheel through one-seventh of a revolution; each of said omitting pins being selectively movable between first and second positions; said pins being moved to said second position only when it is desired to perform an omitting operation; an electric switch; a pivotally mounted switch actuating arm engaged by said timing cam and cooperating therewith to open and close said switch, said switch actuating arm being biased toward said timing cam and being movable toward and away from the peripheral edge of said timing cam in a substantially radial direction relative thereto and having first and second positions corresponding respectively to the open and closed positions of said switch, one of said switch actuating arm positions being further away from said timing cam than the other; and a pivotally mounted omitting arm movable between first and sec ond positions, said omitting arm being biased toward said omitting pins and cooperating therewith to be selectively driven there-by from said first position to said second position only when said omitting pins are in said second position, said omitting pins engaging said omitting arm only when said switch actuating arm is in its position furthest from said timing cam, said omitting arm when at its sec ond position being against said switch actuating arm to prevent said switch actuating arm from moving toward said timing cam.

2. The combination defined by claim 1 in which each omitting pin is labelled in accordance with its corresponding day of the week and a flexible spring blade having one end fixed at its other end normally bearing against the omitting pin corresponding to the proper day of the week during the cycle of operation of the time switch, said end bearing against said omitting pin serving as a detent for said day wheel and having an indicating portion which is Visible at all times and which cooperates with said day wheel to indicate the cycle of said time switch.

3. The combination defined by claim 2 in which said omitting pin engaging end of said spring blade has a portion which normally lies adjacent to and in the path of the next succeeding omitting pin to be moved thereby when the day wheel rotates, said engaging end moving outwardly in a substantially radial direction relative to said day wheel as said next succeeding omitting pin moves, said next succeeding omitting pin eventually clearing said portion after which said engaging end moves back against the pin which moved it to occupy its normal position.

4. The combination defined by claim 1 in which said omitting arm has one end normally in the path of said omitting pins, said omitting pins when in their first position passing over said omitting arm without engaging same and when in their second position engaging said to secure by Letters 7 omitting arm to positively move it to its second position and hold it there until further movement of said day wheel, rsaid omitting pin clearing said omitting armupon further movement of said day wheel whereby said biasing iforce' on said omitting arm causes it to move back to its normal position where it can be engaged by the next succeeding omitting pin.

5. The combination defined by claim 4 wherein said omitting arm is pivoted centrally thereof with one end proximate'to said omitting pins and the other end proximate 'to said switch actuating arm, said omitting arm having a portion intermediate its ends which at all times is supported by and guided within a pair of spaced hear- .ing members, each of said bearing members comprising a post having a peripheral groove which cooperates with ,the edge portion of said intermediate portion of said omitting arm.

8 6. The combination defined by claimS in whichsaid edge of said omitting arm is formed into a stop whicheooperateswith one of said posts to limitjherotation .of said omitting arm when moved by its biasing spring; References Cited in the" file of patent I UNITED STATES PATENTS 1,468,275 Briggs Sept. 18, 1923 "1,970,432 Porter Aug. 14, 1934 2,020,974 Truesdell Nov. 12, 1935 2,034,178 Flegel Mar. 17, 1936 1 2,300,513 Lenehan Nov. 3, 1942' 2,596,330 'Everard May 13, 1952 2,832,856 Goodhouse Apr. 29,1958 

